Templates can be created and sent with advanced fields that have empty
values. That will cause an error when the user tries to sign the
document.
For example, you can create a template with a checkbox field and save
it. Then, you can click the "Use template" button and send the document
by clicking "Send document." However, this shouldn't be possible if the
advanced field doesn't have any values.
Fixes#1259. I literally just used the exact same line of code than from
the document page so it is consistent.
The bug is extremely frustrating because if you make change to the
fields meta on the template and refresh the page, you can't see field
meta (label, default value, required), and neither do your co-workers.
Of course, I tested the change and it now displays correctly the
existing field meta on the template page.
